1. Field of the Invention
The present invention relates to a system to be installed at an interior of a building wall to contain shrapnel from a blast, and a method for producing such systems.
2. Description of Related Art
In the aftermath of recent terrorist attacks, in which buildings have been targeted for destruction, increased attention has been paid to improving the safety of workers inside such buildings, should further attacks be forthcoming. It has been determined that a main source of damage to articles and injury to persons inside of a building under attack is not necessarily the initial blast of an impact or explosion against the building, but instead is the flying shrapnel (pieces of the building wall) generated by the blast.
It has been determined that improvements in containing this shrapnel can be accomplished by spraying a polymeric liner onto the interior surface of the structural wall of a building. A polymer proposed for this application is a polyurethane material that is sprayed directly onto an interior surface of the structural wall. In existing buildings, this liner would be applied by removing any interior cosmetic wall surface (e.g., drywall), applying the spray coating, and reinstalling the cosmetic wall surface. In new buildings, the liner would be sprayed onto the interior of the structural wall prior to the interior finish work being performed.
The in situ spraying of such a liner is a relatively expensive process, and requires skilled equipment operators and careful containment of the area in which the spraying is being performed. In addition, the polyurethane material has a very rapid set or cure time, on the order of only a few seconds. Thus, when the polyurethane is inadvertently sprayed onto surfaces which are not intended to have a liner thereon, it can be very difficult to remove the material from such surfaces.
Polyurea coating materials are generally known for use in applications where corrosion resistance or abrasion resistance is needed or desired, or in certain waterproofing applications. Certain polyurea coatings also are tear and impact resistant.
It is accordingly a principal object of the present invention to provide a system which improves the safety of a building by providing shrapnel absorption and containment, and which provides improved containment of shrapnel generated from an impact or blast at the wall of a building.